Well, if you guys consider a car with higher horsepower means it'll win easily isn't really true. Look at the facts between two cars. The S2000 has an exhaust, a intake, and a tweaked suspension. If you total it up, it really doesn't have that much of an advantage. The G35 still has more power, and probably the same suspension dynamics as the modded S2000. Also, the 2005-2006 S2000s have an additional 15 HP from it's previous year.
Also, even though you guys bash on Hondas, I have to say that they make one of the best transmissions for a stock car. The S2000 is no exception. The guy shifts very smoothly, almost as if it had a semi-racing tranny and all and I also rode in one and the stock one shifts pretty damn smooth and fast. The G35 shifts a bit slower than the S2000.
One more thing, Honda engines are Naturally Aspirated same as the G35, but Honda engines have the advantage. Honda engines are naturally race inspired engines. (Type R Models, S2000, NSX, etc) The redline on most of their engines hit at 9000 rpm, but you can push it further. That's the best thing about them. You can push the engine over the redline and your engine will still hold out. They were engineered that way so that you can use as much power as you can in a gear. That's why S2000s are faster even they're less powered. So, instead of looking at numbers, you gotta look at the stats and design of the car before judging.
As for the G35, that car is just too damn heavy. Take all the technology stuff out, and the back seat, then it can probably eat up that S2000 like nothing because unlike the S2000, it was more torque to push the car further. So yeah, think about it. A coupe vs a roadster. Which is lighter?